The diamond takes a back seat

If you were one of the lucky folks who got engaged over the holidays, chances are you're staring down at a colored stone, and not a traditional diamond. Why the switch? That 18 carat sapphire Prince William planted on Kate Middleton might have something to do with it. (It probably doesn't hurt that it was Princess Diana's engagement ring too.)

"Sapphires are popular right now," says jewelry designer Christopher Duquet (www.christopherduquet.com). "Celebrities or something like the royal engagement always influence fashion to some extent. We've always done sapphire engagement rings, but lately there's been a bump in interest."

Duquet says sapphires are the most popular colored gem to use in engagement rings, and they're also easier to find.

So are sapphires or colored gems less expensive than your basic diamond?

"Not necessarily," says Duquet. "Many colored gemstones are much more valuable than a diamond, but it all depends on the quality of course. A ruby is rarer and more expensive."

That didn't stop former NFL player Eric Johnson from gifting Jessica Simpson with a 5 carat ruby engagement ring last November.

Another pricey and hard-to-find high quality gem is the emerald, but Duquet says those are not the best choice when picking an engagement stone.

"Emeralds are not as durable," he says. "They have natural cleavage planes and it might break. It's not about scratching, it's a chipping issue. An emerald is rarer than a diamond by far, and large emeralds are very expensive and exceed the costs of diamonds, but they don't have the same ability to take wear and tear."

With Valentine's Day just around the corner, Duquet says, you want to know what to look for if you're planning to pop the question with a colored stone.

"if you're picking out a sapphire or a ruby, it's all about the intensity of that stone's color," he says. "For sapphires, you don't want a stone that is too dark or almost black. Also, cloudiness is not a good sign with any colored stone.

"And with a ruby, the pinker ruby will be less expensive than a pure red ruby. Just as with a diamond, your clarity, color, and cut are all important, but colored gems are not as scrutinized as the diamonds."

Duquet says you can have an impurity in a colored gem, but if the color is intense, that shouldn't be a deal breaker. "Sapphires and rubies are the same mineral -- corundum -- and they are colored by different trace elements," he says. "What you want is an intense hue or saturation. If the inclusions are not seen with the naked eye but color is incredible, that's an amazing stone."

One colored stone that Duquet isn't getting many requests for these days is the pink diamond.

" Jennifer Lopez made those popular," says Duquet. But just as her relationship to Ben Affleck fizzled, so has the trend for pink sparklers. "We also don't see many requests for yellow diamond engagement rings anymore. If there is color in the engagement ring, it's going to come from another stone, and not a diamond."